Less than one week out from Election Day, the midterm focus remains where it’s always been: on the battle for control of the U.S. House and Senate, the outcomes of which will go a long way toward shaping the next two long years of Donald Trump’s presidency.

But there’s plenty of action further down the ballot that will matter, too. Plenty of it. All told, nearly 10,000 candidates are running in more than 6,000 elections, spread out over 46 states. According to nonpartisan handicappers, as many as 17 individual legislative chambers have the potential to flip this fall, of which 11 are currently held by Republicans, four are controlled by Democrats, and two are evenly split between the two parties. And if that isn’t enough to work you into a bewildered electoral lather, there’s this: Roughly 800 of the state lawmakers selected next week will win four-year terms, meaning most of those will still be in office when their states redraw their congressional maps after the 2020 census.

Where, though, should you focus your limited attention as the results trickle in on election night? These four state Senate races are arguably the most consequential of any on the calendar. Each could prove the difference between single-party and split control of a state government, which means each could have an outsized impact on everything from a woman’s access to abortion, to workers’ right to unionize, to citizens’ ability to cast a ballot.

Colorado Senate District 24

The Colorado Legislature is currently split, with Democrats enjoying a comfortable, and likely safe, 36–29 cushion in the House and with Republicans holding a much narrower 18–17 advantage in the Senate (counting an independent senator who caucuses with Democrats). That’s where SD-24 comes into play. Democrats consider it their best chance to pick up the seat they need to end GOP control of the upper chamber, and potentially give them the coveted state-level “trifecta” in process, assuming Democrat Jared Polis can prevail in the gubernatorial race as well.

Humenik won her first term narrowly in 2014, the same year the GOP broke Democrats’ hold on the state capitol and also posted strong gains nationally. But Democrats are hoping that Winter can ride a blue wave to victory in this district, which voted for Hillary Clinton by 5 percentage points two years ago and includes parts of suburban Denver. Humenik, a relatively moderate Republican, is hyping her bipartisanship while pointing to the state’s economy to argue for why she deserves another term. Winter, meanwhile, is running on a platform that includes improving affordable housing and addressing climate change, things she says won’t get done in a divided government.

Connecticut Senate District 4

Democrats have the chance to reclaim the trifecta in Colorado, but they could lose the one they have in Connecticut. Republicans have an outside chance of winning the governorship and the state House of Representatives, which Democrats control 80–71 at the moment. But the GOP’s best blue-to-red opportunity is actually in the Senate, where they need to flip just one seat to resolve the current 18–18 tie, which has been broken the past two years by the Democratic lieutenant governor.

The GOP hasn’t controlled either chamber since the mid-’90s, but the party sees an opening this year thanks to outgoing Democratic Gov. Dannel Malloy, who is among the least popular governors in the nation. Outside conservative groups are doing their best to tie Cassano to Malloy, while Democrats are hoping Trump drags down Tweedie. Given that the district, which sits just east of Hartford, went for Hillary Clinton by 20-plus percentage points, a GOP victory in SD-4 seems a stretch. But knocking off the incumbent would be a major blow to Democrats in a deep-blue state, and it would cost them one of just eight state trifectas they have today.

Maine Senate District 11

The Maine Legislature is currently split, but it might not be after the midterms. Democrats hold a narrow 74–70 advantage in the House, which they are slight favorites to hold. Republicans, meanwhile, have an even narrower 18–17 hold on the Senate, which could go either way. Democrats have a handful of opportunities to net the single seat they need, but the one at the top of their wish list is SD-11, where the current senator, Republican Mike Thibodeau, is term-limited. Thibodeau won re-election by 800-odd votes in 2016, when the district went for Clinton by about 130 votes.

If Democrats can flip this one, they’d likely be on their way to winning control of the entire Legislature. If Republicans can hold the seat, it’s not outside of the realm of possibility that they could turn this purple state into a trifecta of their own, depending on how their nominee fares in the race to replace outgoing Gov. Paul LePage.

Minnesota Senate District 13

There’s no complicated guesswork or hypotheticals when it comes to Minnesota. The only state Senate race on the ballot is this special election, and it will decide control of the upper chamber, which was split 33–33 after Republican Michelle Fischbach gave up the SD-13 seat to officially become lieutenant governor in May. In a normal year, Democrats might not even bother to compete in this one since Trump won the reliably conservative district in a blowout. But Democrats can’t help but make an effort here, given that it’s their only path to Senate control and because winning it would mean that no matter what else happens in the state, the GOP wouldn’t be able to add Minnesota to its current total of 26 state trifectas.

The question that could decide those four races—along with countless others—is just how big the blue wave turns out to be. Despite these races being local by definition, national politics is never far away. There have been 30 midterm elections since the start of 1900, and according to the National Conference of State Legislatures, in all but two the president’s party has lost state legislative seats—an average of more than 400 each time.

The past two midterms were particularly rough for Democrats, who had full control of state legislatures in 27 states during Barack Obama’s first year in office and just 11 in his last year. That trend was exacerbated when the GOP used the power it gained in the 2010 elections to redraw many state legislative maps in their favor. Democrats won’t have the chance to return that gerrymandered favor until after the next census, and the vast majority of lawmakers who will play a role in that process will need to win in 2020. Winning big in 2018, however, could give Democrats the state-level footholds they’ll need to do just that.

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